Regarding such secondary batteries, Patent Literature 1, for example, discloses a secondary battery comprising a porous electron insulating layer adhered to the surface of at least one electrode selected from the positive electrode and the negative electrode. The porous electron insulating layer contains a fine particle filler and a resin binding agent and the fine particle filler is a particle containing a particle with indefinite shape in which a plurality of primary particles are linked and bonded. As the fine particle filler, titanium oxide (titania), aluminium oxide (alumina), zirconium oxide (zirconia) and tungsten oxide are mentioned.
Patent Literature 2 discloses a non-aqueous electrolyte secondary battery having, on the surface of the positive electrode and/or the negative electrode, a porous separator material for separating the positive electrode and the negative electrode. The separator material contains a cross-linked resin and has sufficient strength and resistance to a non-aqueous electrolyte. As the cross-linked resin, crosslinked materials are mentioned such as at least one resin selected from the group consisting of polyethylenes (PEs), polypropylenes (PPs), copolymerized polyolefins, polyolefin derivatives (chlorinated polyethylenes and the like), styrene-butadiene copolymers, acryl resins [polyalkyl(meth)acrylates and derivatives thereof such as polymethylmethacrylate, polymethylacrylate and the like], polyalkylene oxides [polyethylene oxide (PEO) and the like], fluororesins [polyvinylidene fluoride (PVDF) and the like] and derivatives thereof, urea resins, polyurethanes, epoxy resins, unsaturated polyester resins, polyamide-imides, polyimides and the like.
Patent Literature 2 also discloses the separator material which may contain various inorganic fine particles for improvement of the strength thereof. The inorganic fine particles include, but not limited to as far as they are electrochemically stable and have electrical insulating properties, oxide powder such as iron oxide, SiO2 (silica), Al2O3 (alumina), TiO2, BaTiO3 and the like; nitride powder such as aluminium nitride, silicon nitride and the like; covalent crystal powder such as silicone, diamond and the like; sparingly soluble ionic crystal powder such as barium sulfate, calcium fluoride, barium fluoride and the like; montmorillonite and the like.
Patent Literature 2 also discloses the separator material which contains fine particles melting at 80 to 150° C. such as polyolefin fine particles for conferring shut down behavior on a battery. As a resin forming such fine particles, for example particles of PEs, copolymerized polyolefins, polyolefin derivatives (chlorinated polyethylenes and the like), polyolefin wax, petroleum wax, carnauba wax are mentioned. Exemplified copolymerized polyolefins include ethylene-vinyl monomer copolymers, more specifically ethylene-vinyl acetate copolymers (EVA), ethylene-acrylic acid copolymers (ethylene-methyl acrylate copolymers, ethylene-ethyl acrylate copolymers and the like) and the like.
Patent Literature 3 discloses formation of a sheet-shaped electrode containing an active material-containing layer formed on a current collector by mixing an electrode active material and a binder to prepare an application solution for electrode formation, applying the application solution on the current collector and then drying the application solution. It also discloses the sheet-shaped electrode which is then extended by applying pressure and cut into a predetermined dimension. Patent Literature 3 proposes a slitter device which allows sufficient prevention of melt-adhesion of scrapings from the current collector onto the side of an upper blade upon cutting of the sheet-shaped electrode and allows sufficient prevention of generation of burrs on a cutting plane of the current collector.